.travis.yml in sidekiq_prometheus-1.9.0 vs .travis.yml in sidekiq_prometheus-2.0.0

@@ -3,5 +3,8 @@
 rvm:
   - 3.1
   - 3.0
   - 2.7
 before_install: gem install bundler -v 2.2.15
+gemfile:
+  - sidekiq_6.gemfile
+  - sidekiq_7.gemfile